How to import 3D objects
You go to a website that offers free 3D objects, for example
Look for some, for example here I searched for a hat.
Download the 3D object in COLLADA format (with .dae at the end) to your PC.
If the object is not in COLLADA format, you can convert it to COLLADA for example :
On Planet, click OBJECT > NEW
Type an object name, go to the TOOLS tab and click on IMPORT COLLADA.
you may have an error message when importing, often because the object
has too many triangles or that the terrain where you are importing has no more space.
And here's your hat !
All you have to do is apply a texture and resize it with STRETCH option 3d.
If your object consists of several meshes, you should link it first (mode LINK, option LINK ALL VOLUMES)
in order to be able to resize all the parts at the same time.
How to turn your camera in blender
Use the numeric keypad keys (2, 4, 6, 8) to turn your camera.
Keep the Ctrl key pressed + use the numeric keypad keys (2, 4, 6, 8) to move your camera.
Use the mouse wheel to zoom in.
How to reduce the number of triangles of an object in blender
You see that the stool has 3846 triangles.
Select a part of the stool with a right mouse button click, it will be surrounded by a yellow line.
If you want to DELETE this part, press the Delete key and it's done.
Otherwise, to reduce, continue below ..
Click on the small key.
Click on "Add Modifier" and then on "Decimate".
Click on "Planar", type 11d (that means 11 degrees), check "All Boundaries", click on "Normal".
Click on "Apply" and you see that the number of triangles has decreased.
Repeat the operation for each volume (= geometrical shapes of the object) by right-clicking on it so that it is surrounded by a yellow line.
(Here after processing the feet of the stool, we will do the sitting part)